Textile threads and fabrics



Patented Aug. 3, 1937 UNITED STATES PATENT OFFICE .Wliitehead, Cumberland, Md.,

assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application February 5, 1936, Se-

rial No. 62,476. In Great Britain February 9,

7 Claims 10 highly twisted threads of natural silk in the gummed state, thecrepe effects appearing mainly when the fabrics so formed are subjected to an aqueous scouring treatment. The fabrics obtained by this process are highly valued on account of their pleasing appearance and handle.

The production of crepe fabrics in an analogous manner by the use of crepe threads of cellulose acetate has, however, been accompanied by difliculties. Generally, the crepe effect obtained by simply applying to a cellulose acetate thread a twist of the order of that commonly employed in connection with natural silk, weaving the twisted threads into a fabric and scouring the latter, is very unsubstantial and not comparable with that obtained with natural silk or regenerated cellulose artificial silk.

According to the present invention highly twisted crepe threads of filaments of an organic derivative of cellulose are produced from threads of filaments of an organic derivative of cellulose by crepe twisting in at least twostages and steaming the threads during the insertion of twist in the final stage of twisting. It is of great advantage to havemoisture present during the steaming.

Good results may be obtained by steaming at above C. Steaming temperatures in the neighbourhood of C. are especially to be recommended.

The invention is of especial value and will be more particularly described in connection with" the production of crepe threads of filaments of cellulose acetate.

The advantages of the new process may be obtained when the thread is Steamed during the insertion of twist both in the final stage of twisting and in an earlier stage or stages of twisting. In fact it is of great advantage to eflect in the presence of steam any insertion of twist beyond the point at which twisting would result in weakening of the thread if the said twisting were effected without the steaming. The precise degree of twist beyond which it is important to steam during twisting depends upon the total denier of the thread and the number of its constituent filaments. Generally at least the last half or two thirds of the total crepe twist should be applied while steaming. I

In this way it has been found possible to produce crepe threads of filaments made from and consisting of cellulose acetate, which yield fabrics exhibiting remarkably good crepe efiects. Moreover, by this new process crepe threads of cellulose acetate filaments may be. produced which have an average strength much greater than that of crepe threads produced by a simple twisting operation without the steam treatment during twisting. Further, apart from the great advantage of a stronger resultant thread the twisting operation itself is greatly facilitated in that twisting may satisfactorily be accomplished under conditions of twist and spindle speed which in the absence of the steaming would give rise to frequent thread breakage and render impossible the insertion of the desired twist or at least lead to a very weak and useless thread.

The threads may consist of substantially continuous filaments of cellulose acetate or they may contain discontinuous filaments of cellulose acetate, the length of which may vary within wide limits. For example the threads may be those spun from a mass of discontinuous filaments or those prepared in the manner described in British Patents Nos. 424,683, 424,752, 424,830 and 424,879. Again the crepe threads may be made with filaments which contain water-insoluble compounds, whether'compounds of pigment-like character in such form as materially to modify the lustre of the filaments (e; g. barium sulphate or titanium dioxide), or loading metal compounds, for example tin compounds.

In carrying out the new process the thread .may be twisted by the rotation of a package from which it is being drawn off through a guide fixed substantially in line with the axis of rotation of the package, and thereafter wound on a bobbin or the like the thread being passed, on its way from the guide to the bobbin, through steam under conditions such that moisture is present.

On the other hand, any other suitable crepe twisting device may be employed. For example, a ring twister may be used when crepe twisting (thread consisting of discontinuous filaments.

The twisting spindle, the guide fixed in line with the axis of the spindle, and the steaming device should be so arranged that twist resulting from the rotation of the package is inserted while the thread is under the influence of the steam. For example, when twisting the thread be provided with a small chamber situated verby the rotation of a package from which the thread is being drawn off, if the freedom or the thread to rotate within the balloon guide or other guide preceding or forming part of the steaming device is unduly restricted, e. g. by'causing the yarn to change direction materially at the guides, the insertion of twist while the thread is under the influence of the steam may be restricted to an undesirable extent, or substantially prevented, and the resulting crepe threads may nothave the valuable properties which may otherwise be secured. Thus, when using a twisting device of the kind in which thread is drawn oil from a rotating package, it is advantageous to arrange that the path of the thread after leaving the balloon guide and through the steaming device, is substantially in line with the axis of the twistingspindle.

In the case of a ring twister, where twisting is effected by the rotation of a package on to which the thread is being wound, the thread passing through steam on its way from the let-ofidevice to the twisting spindle, a change of direction at the point where the thread leaves .the steaming .device is of less importance as the thread remains under the influence of the steam for a short time after leaving the steaming device.

The phrase twist is inserted while the thread is under the influence of steam means that that portion of the run of the thread in which twist is being inserted is either in the steam or still under the influence of the steam.

If desired, the above-mentioned twisting devices, in which the thread is drawn off from a rotating package, may be provided with a device which restricts the ballooning of the yarn or the tendency of twist to run back to the package. As, examples of such devices may be mentioned flyers and the floating ring device described in U. S. Patent No. 1,784,581.

Steaming may conveniently 'be effected by allowing the thread to pass through a suitable chamber supplied with steam under such conditions that moisture is present. 1

Thus, a vertical twisting spindle of the type in which thread is drawn oil upwardly over the end of a rotating package through a guide substantially in line with the axis of the spindle, may

tically above the spindle. The chamber is provided with small holes, top'and bottom, to permit passage of the thread, and also with a steam inlet. If desired, a single steam chamber may be arranged to serve a number of spindles, being provided with inlet and outlet holes for the thread of each spindle. Such an apparatus may conveniently consist of a horizontal pipe mounted over a row of spindles and provided with eyes of porcelain, stainless steel, or other suitable material at. appropriate points on top and bottom for the entrance and exit of the threads. The diameter. of the pipe is sufficient to afiord the thread the requisite length of travel in the steam. Steam may be admitted to the pipe at one point or at more than one point as may be necessary according to the length of the pipe, to secure sufliciently uniform conditions of steaming as between the threads from the difierent spindles.

At the point at which the thread from the twisting. spindle enters the steaming device, it is advantageous to arrange a free escape of steam on to the thread as it is drawn ofi from the spindle. A shield, for example in the form of a funnel, may, if desired, be fitted around the thread approaching the steaming device in order to maintain an atmosphere of steam around the thread.

The presence of the desired moisture may be assured by arranging for the condensation of steam. Dry steam may be passed through water so as to saturate the steam and the requisite moisture produced by cooling in the steaming device.

Another method of ensuring the presence of moisture is to wet the thread with water; for example the bobbins of thread may be wetted 1 before the-twisting operation or better, water may be'applied to the thread, by means of a wick or other device, after the thread leaves the spindle and prior to its entering the steaming device. The water may contain a substance which facilitates wetting of the thread by water.

- Steam at about atmospheric pressure, e. g. slightly above atmospheric pressure, is most conveniently employed. If desired, however, the steaming may be effected with steam at higher pressures, e. g. steam at -25 lbs. per square inch.

A steaming treatment of relatively short duration such as may be secured by passing the yarn at a speed of from 2 to 10 metres per minute through 3" of steam has been found to give satisfactory results. Lengthier treatments may, however, be employed, for example the yarn may be passed'at the said speeds through Bto 12" of steam or more.

The cellulose acetate filaments of the threads very readily undergo stretching when the threads are twisted under the influence of the steam and moisture. The amount of stretch may be measured by comparing-the original thread denier with the final thread denier (after ,untwisting). The denier of the resultantthread is, in general,

owing to imparted stretch, less and even substanthread is from to particularly IOO to 110% of that of the thread before crepe twisting,

especially in the case of threads having an original denier of 150 or less Good crepe fabrics may however be obtained when the final denier is still greater, for example up to. of that of the thread before twisting when threads having a denier about" 200 are employed.

The total twist inserted in accordance with the new process may vary within wide limits. The new process possesses the feature that it enables a very high degree of twist to be inserted without the great weakening of the thread such as is generally experienced when a cellulose acetate thread is twisted without the steaming to the degree necessary in a crepe thread. The process, moreover, permits the insertion of twists which are impossible of attainment without the steam,-'

. ing owing to breakage of the thread. This is twist of about 70 to '75 turns per inch is desirable, and with threads of 115 denier twist of about to turns per inch. With these indications it is a simple matter to determine the desirable twists for threads of other deniers. .The denier numbers given are those of the threads after crepe twisting.

The twist may be divided between the twisting stages in various proportions. Twist inserted in the absence of steam should not be of such degree as to damage the thread. To this end, as indicated previously, twisting in the absence of steam should not be effected where the twist inserted is sufficient to result in substantial weakening of the thread.

A particularly convenient method of working is to apply about one sixth to one quarter or one half of the total crpe twist without steam, say up to 10 or 15-25 or even up to 30 or 40 turns per inch, and then to complete the crepe twist in the presence of steam and moisture.

As indicated above, by the new process highly twisted threads of cellulose acetate filaments may be produced which are of high crping power. In these threads the filaments are ex tremely closely packed, a feature to which their good crping power may be attributed. For example, the filaments may be so closely packed that the apparent specific gravity of the thread as determined from the diameter and the denier is more than 85%, e. g. 85 to 90% of the actual specific gravity of the filaments, and that distortion of the cross-section of at least some of the filaments has occurred during the process of twisting. The filaments of the thread, however, are not stuck together and can be separated upon untwisting. Moreover, these cellulose acetate crepe threads are smooth and cylindrical as opposed to the rough feel and helical form of a cellulose acetate thread or a viscose thread which has been crepe twisted in the ordinary way. Further, in comparison with these latter threads, the smooth cylindrical cellulose acetate crepe threads exhibit much less tendency to snarl or kink.

While the new process enables production of threads which yield satisfactory crepe eifects without a special treatment, other than the twisting and steaming treatment characteristic of the process, other devices and treatments may, if desired, be employed further to improve the properties of the crepe threads and/or fabrics produced therefrom. For example the crpe threads may be sized at any suitable stage of their manufacture, for example in the course of winding on to the bobbin from which twisting is effected. In this connection, particular mention may be made of sizing materials selected in accordance with the considerations laid down in U. S. Patent No. 2,007,182. For example a casein, egg-albumen, or other size which is not very readily removed by aqueous treatments may be employed. Another size whichmay be employed is a drying 011, if desired one which has been partially oxi-' dized, e. g. boiled or blown linseed oil.

The highly twisted crepe threads may be incorporated in the fabrics in various ways, for example the weft alone may be wholly or partially composed of such threads or the warp may also contain them. Valuable fabrics may be produced by employing warp threads of relatively low twist and in the weft both crepe threads having a left-hand twist and crepe threadshaving a right-hand twist, pairs of threads of left-hand u silk or regenerated cellulose.

Fabrics containing highly twisted crepe threads prepared in accordance with the invention may subsequently be given a hot aqueous treatment, for example in the manner commonly adopted in connection with fabrics comprising highly twisted yarns of natural silk. Enhanced crepe effects may be obtained by means of hot aqueous treatments at or near the boiling point.

Instead of threads of filaments made from and consisting of cellulose acetate, threads of filaments of other organic derivatives of cellulose may be crepe twisted in a similar manner. As examples of such other organic derivatives of cellulose may be mentioned cellulose formate, propionate or butyrate, or other organic esters of cellulose, and methyl, ethyl, benzyl and other ethers of cellulose.

Having described our invention what we desire to secure by Letters Patent is:'

1. Process for the production of a highly twisted crepe thread of filaments of an organic derivative of. cellulose, which comprises crepe twisting a. thread of filaments of an organic derivative of cellulose in at least two stages and inserting twist in at least the final'stage while the thread is subjected to the action of steam.

2. Process for the production of a highly twisted crepe thread of filaments of an organic derivative of cellulose, which comprises crepe twisting a thread of filaments of an organic derivative of cellulose in-at least two stages and inserting twist in at least the final stage while the thread is subjected to the action of moist steam.

3. Process for the production of a highly twisted crepe thread of cellulose acetate filaments, which comprises crepe twisting a thread of cellulose acetate filaments in at least two stages and inserting twist in at least the final stage while the thread is subjected to the action.

of steam.

4. Process for the production of a highly twisted crepe thread of cellulose acetate filaments, which comprises crepe twisting a thread of cellulose acetate filaments in at least two stages, of which the final stage involves insertion of at least half of the total crepe twist, and inserting twist in the final stage while the thread is being steamed. I

5. Process for the production 01' a highly twisted crepe thread of cellulose acetate filaments, which comprises crepe twisting a thread of cellulose acetate filaments in at least two stages, and inserting twist in at least the final stage while the thread is being steamed with moist steam, the filaments of the thread being stretched by 5 to 25% of their original length.

6. Process for the production of a highly twisted crepe thread of cellulose acetate filaments, which comprises crepe twisting a thread of cellulose acetate filaments in at least two stages, and during the final stage oi. twisting steaming the thread by passing it through a substantially closed chamber maintained full of steam under conditions such that moisture is present, so that twist is inserted as the thread passes through the steaming chamber, the iinal stage of twisting being eflected by the rotation of a package from which the thread is being drawn.

7. Process for the production of a highly twisted crepe thread of cellulose acetate filamerits, which comprises crepe twistinga of cellulose acetate filaments in at least two 10 stages, and during the final stage of twisting thread CERTIFICATE OF connection.

Patent No. 2,088,587.

August 3, 1957.

HENRY 'DREYFUS, ET AL'.

It is hereby certified that error appears in the printed s of the above numbered patent requiring correction as follows: Page 3, second column, line '75, claim 6, andpage 4, second column, line 1-2, claim '7, strike out the words "substantially closed; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of October, A. D. 1937.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

pecificati'on steam under conditions such that moisture is present, so that twist is inserted as the thread passes through the steaming chamber, the iinal stage of twisting being eflected by the rotation of a package from which the thread is being drawn.

7. Process for the production of a highly twisted crepe thread of cellulose acetate filamerits, which comprises crepe twistinga of cellulose acetate filaments in at least two 10 stages, and during the final stage of twisting thread CERTIFICATE OF connection.

Patent No. 2,088,587.

August 3, 1957.

HENRY 'DREYFUS, ET AL'.

It is hereby certified that error appears in the printed s of the above numbered patent requiring correction as follows: Page 3, second column, line '75, claim 6, andpage 4, second column, line 1-2, claim '7, strike out the words "substantially closed; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of October, A. D. 1937.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

pecificati'on 

